Polarizing plates according to the related art generally have a structure in which protective films are attached to both surfaces of a polarizer formed of a polyvinyl alcohol (hereinafter, referred to as ‘PVA’)-based resin dyed with a dichroic dye or iodine, using an adhesive. However, as of late, as the thinning of display devices has proceeded, the development of single-sided polarizing plates respectively including a protective film only formed on one surface of a polarizer and a pressure sensitive adhesive (PSA) directly formed on the other surface of the polarizer, without the protective film, has been undertaken. However, in the case of single-sided polarizing plates including the pressure sensitive adhesive (PSA) directly formed on the polarizer as described above, since durability properties thereof may be defective, cracks may be easily generated in the polarizer under severe conditions. Further, curling may be caused due to a difference in shrinkage rates between the protective film and the pressure sensitive adhesive (PSA), thereby leading to a light leakage phenomenon in the case that the polarizing plate is mounted on a display device.
In order to solve the limitations as described above, a technology of forming a protective layer between a polarizer and a pressure sensitive adhesive (PSA) of a single-sided polarizing plate using a curable resin has been suggested. Korean Patent Laid-Open Publication No. 2011-0014555 teaches a polarizing plate including a protective layer provided between a polarizer and a pressure sensitive adhesive (PSA) and having a tensile modulus of 100 MPa or above. However, in the case of a hydroxyethyl acrylate resin used as a protective layer forming agent in the Patent Publication, durability and optical characteristics of the polarizing plate may be deteriorated under high humidity conditions due to low water resistance and glass transition temperature properties thereof.